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Updated: Feb 14, 2026

Synthesis of 1,2-Azaborines and the Preparation of Their Protein Complexes with T4 Lysozyme Mutants
Published on: March 25, 2017
The Dewar Isomer of 1,2-Dihydro-1,2-azaborinines: Isolation, Fragmentation, and Energy Storage
Klara Edel1, Xinyu Yang2, Jacob S A Ishibashi2
1Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Abstract:
The photochemistry of 1,2-dihydro-1,2-azaborinine derivatives was studied under matrix isolation conditions and in solution. Photoisomerization occurs exclusively to the Dewar valence isomers upon irradiation with UV light (>280 nm) with high quantum yield (46 %). Further photolysis with UV light (254 nm) results in the formation of cyclobutadiene and an iminoborane derivative. The thermal electrocyclic ring-opening reaction of the Dewar valence isomer back to the 1,2-dihydro-1-tert-butyldimethylsilyl-2-mesityl-1,2-azaborinine has an activation barrier of (27.0±1.2) kcal mol-1 . In the presence of the Wilkinson catalyst, the ring opening occurs rapidly and exothermically (ΔH=(-48±1) kcal mol-1 ) at room temperature.
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